Folding bicycle

ABSTRACT

In the riding mode, the folding bicycle has the same geometry that defines the riding characteristics and ergonomics in a usual bicycle, and has in the storage or portable mode the dimensions that fit into the trunks of small-sized cars, while allowing folding without the use of tools and in riding mode having no gaps between the detachable parts. The bicycle has the front fork ( 4 ) with the fork blades ( 6 ) bent forward and equipped with two backwards-pointing swing-arms ( 7 ), which hold the front wheel ( 3 ) in such a way that its position remains the same as in a usual bicycle and can be adjusted to riding preferences. The swing-arms ( 7 ), which are attached to the fork blades ( 6 ), rest on the end parts ( 13 ) and are bound by the springs ( 14 ). In the riding mode, the springs ( 14 ) keep the swing-arms ( 7 ) constantly pressed against the end parts. The rear wheel ( 18 ) can be folded by turning it together with I the chain stays ( 17 ) around the pivot ( 19 ) with an attached coaxial shaft ( 22 ), which holds a pair of sprockets ( 23,24 ). The cranks ( 16 ) and the sprocket ( 32 ) on the rear wheel ( 18 ) are connected by two chains ( 25, 31 ).

FIELD OF THE INVENTION

The subject of invention is a bicycle, which can, without the use oftools or any special knowledge or skills, quickly and easily be foldedinto such a shape and dimensions that it can be put into the trunk ofany average-sized car, and is portable as well, while preserving theriding characteristics of a non-folding bicycle.

BACKGROUND OF THE INVENTION

The technical problem the invention solves is how to design a foldingbicycle, which has in the riding mode the same geometry that defines theriding characteristics and ergonomics in a usual bicycle, and has in thestorage or portable mode the dimensions that fit into the trunks ofsmall-sized cars, while allowing folding without the use of tools and inriding mode having no gaps between the detachable parts.

Known folding bicycles typically have a two-piece frame, which can bedismantled, folded or telescopically shortened. To reduce the dimensionsin the portable mode, both smaller-sized wheels can also be removed. Thedisadvantage of all the solutions is that the joints between the frameparts gradually develop a certain gap, or the joints themselves are theweak points in the construction that gradually lead to a breakdown.Another disadvantage is that the frames are usually shorter and thusergonomically unsuitable for the rider's size. The result of this isthat one cannot comfortably ride such a bicycle on a greater distance,the rider is less energy efficient, and the riding characteristics areless favorable due to the different position of front wheel and smallerwheel size compared to the non-folding bicycles.

SUMMARY OF THE INVENTION

The technical problem described above is solved by the bicycle, which isthe subject of the present invention. A main feature and innovation isin the fact that the shape and size of the frame remains the same as ina usual non-folding or rigid men's or women's bicycle. One innovation isthe front fork, which enables turning by 180 degrees and folding of thefront wheel towards the down tube, while in the riding mode preservingthe same angle as in usual bicycles. The down tube is made of two tubeswith a slot in between to slide the front wheel into. The handlebar canalso be folded towards the frame. Since the diameter of the wheels areonly of the 16″ size or 23″ diameter, the length of the bicycle foldedin such a way enables transportation in the trunk of small-sized car. Ifthe rear wheel is removed, the length of the folded bicycle may befurther reduced to the length of the frame, although in one embodiment,the rear wheel is foldable as well.

The chain stays, together with the rear wheel, is foldable upwardstoward the seat. To facilitate the folding of the chain stays and therear wheel, the transmission from the chainring to the sprocket iscomplemented by two sprockets and a shaft, i.e. consists two chains inseries, which results in an additional transmission ratio. The shaftalso serves as a pivot, around which the chain stays and the rear wheelfold. The front chain remains between the front chainring and thesprocket on the shaft, while the rear chain remains between the frontsprocket and the rear sprocket, and shifts upwards together with thechain stays and the rear wheel without changing the distance between thefront sprocket and the rear sprocket. To reduce the width of the foldedbicycle, the pedals can also be folded.

Such a bicycle can also be arranged as a tandem, without extending. Dueto the normal frame size and the small-sized wheels, the bicycle can beequipped with an electric or internal combustion motor withoutincreasing the folded dimensions. Since the geometry of the bicycle isidentical to the geometry of a usual bicycle, the riding characteristicsremain the same, so the bicycle is suitable for longer trips as well.Transmission gears, preferably internal, can improve the ridingcharacteristics. The gear unit can be placed in the rear hub, on themiddle shaft, or in the bottom bracket.

The weight of such a bicycle is the same or less than in usual bicycles,so in portable mode it can be carried around, possibly in a speciallydesigned bag or backpack.

The front forks allow installation of shock absorbers, which increasethe stability of the bicycle, as well as the comfort of the ride.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary embodiments of the invention will be explained in detail withreference to the following figures in which like reference numeralsrefer to like parts throughout:

FIG. 1 is a schematic of a first embodiment of a folding bicycle in ariding mode accordance with the present invention;

FIG. 2 is a the schematic of a first embodiment of a folding bicycle ina portable mode in accordance with the present invention;

FIG. 3 illustrates a tandem version of a folding bicycle in accordancewith the present invention;

FIG. 4 is a schematic of a second embodiment of the folding bicycle inthe riding mode, in accordance with the present invention;

FIG. 5 illustrates a folding bicycle with an auxiliary engine inaccordance with the present invention;

FIG. 6 illustrates a women's version of a folding bicycle in accordancewith the present invention;

FIG. 7 illustrates a folding pedal of a bicycle in the riding mode inaccordance with the present invention; and

FIG. 8 illustrates a folding pedal in a folded position in accordancewith the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following paragraphs, the present invention will be described indetail by way of example with reference to the drawings. Throughout thisdescription, the preferred embodiment and examples shown should beconsidered as exemplar, rather than as limitations on the presentinvention. As used herein, the “present invention” refers to any one ofthe embodiments of the invention described herein, and any equivalents.Furthermore, reference to various feature(s) of the present inventionthroughout this document does not mean that all claimed embodiments mustinclude the referenced feature(s).

The folding bicycle comprises a frame (1) of any known geometry,designed according to the rider's size and riding preferences. The downtube (2) may include two tubes with a gap between them (2′), which isapproximately the same or wider than the width of the front wheel (3).The front fork (4) is attached to the frame (1) at the bearing (5). Thefork blades (6) are bent forward and equipped with twobackwards-pointing swing-arms (7), which hold the front wheel (3) insuch a way that its position remains the same as in a usual bicycle andcan be adjusted to riding preferences. The swing-arms (7) are connectedby a stirrup (8), which encloses the wheel (3). Its top is pressedagainst the joint (9) of the front fork (4) directly under the bearing(5). The two parts can merely touch or can be connected by a shockabsorber, preferably an elastomer type. The stirrup (8) is connected tothe fork (4), preferably in the area of the joint (9), by a manuallyreleasable connection (12), preferably a spring lock.

In the other example, as illustrated in the second embodiment of thefolding bicycle illustrated in FIG. 4, the swing-arms (7), which areattached to the fork blades (6), rest on the end parts (13) and arebound by the springs (14). In the riding mode, the springs (14) keep theswing-arms (7) constantly pressed against the end parts. The end parts(13) can be replaced by the shock absorbers (14′), such as preferablythe elastomer type, or the hydraulic or pneumatic type.

In the first example, when the connection (12) is released and the frontwheel (3) on the swing-arms (7) is turned forwards by approximately 180degrees, or in the second example, when the swing-arms (7) are turned bystraining the springs (14), so that the springs (14) hold the frontwheel (3) next to the fork blades (6), and when the fork (4) is turnedby 180 degrees, the front wheel (3) is fixed in the gap (2′) between thetwo down tubes (2) of the frame (1). Such folding of the front wheel (3)and the fork (4) is possible without the use of any tools in thepreferred example. It decreases the dimensions of the bicycle in theportable mode without altering the riding characteristics in the ridingmode.

The chainring ) and the cranks (16) are mounted to the frame in anydesired fashion and at any desired position. The rear wheel (18) can befolded by turning it together with the chain stays (17) around the pivot(19), which is placed on the frame (1), between the chainring (15) andthe rear wheel (18).

From the frame (1), preferably from a point close to the chainring (15),a preferably double bracket (20) extends towards the rear wheel (18). Atthe end of the bracket (20) there is a bearing assembly (21) with ashaft (22), which holds two coaxial sprockets (23) and (24). Thechainring (15) and the sprocket (23) are connected by the front chain(25). The chain stays (17) are attached to the bearing assembly (21),and have dropouts (27) in which the rear wheel (18) is attached. Theseat stays (28), which are connected to the chain stays (26), arereleasably connected to the strut (29), protruding from the frame (1).Preferably, they are connected by a quick-release mechanism. Between thestrut (29) and the seat stays (28), a shock absorber can be fitted aswell.

The rear wheel (18) is mounted in the dropouts (27). By its sprocket(32), the rear chain (31), the sprockets (24) and (23), the front chain(25) and the chainring (15), it is connected to the cranks (16). Therear hub can also be equipped with internal gears, which are not shownin the figures. The internal gears can also be placed on the bearingassembly (21), or in the bottom bracket (16). External gears on the rearwheel can also be used, but would be less favorable due to the smallsize of the wheel and the length of the derailleur, which would be tooclose to the ground.

When the quick-release mechanism (30) is released, the chain stays (17),the rear wheel (18) and the rear chain (31) are pivoted around the shaft(22) towards the frame (1) without changing the distance between thechainring pairs. Therefore, it is not possible for the chains to comeoff during the folding and unfolding of the bicycle. Such a design alsopermits the use of two chain covers, which do not hinder the folding ofthe rear wheel and the chain stays. The chain covers are not shown inthe figures.

In one embodiment, as illustrated in FIG. 5, a drive mechanism (65) isprovided. The drive mechanism can be mounted in any fashion. Forexample, it is mounted to frame (1) and provides a motive force viaconnection to one of the sprockets (23, 24 or 32), or chainring (15).Examples of drive mechanisms (65) are an electrical motor or an internalcombustion engine.

In an alternative embodiment, as illustrated in FIGS. 5 and 6, the rearwheel (18) is removable father reducing the length of the folded bicycleto the length of the frame. In addition, in an alternate embodiment,quick release mechanism (30) is not provided, making strut (28) andstays (29) in fixed relation to one another.

In the other example, the chain stays (17) can be folded around thepivot (19) and are equipped with a locking device, preferably a pin.They can also be equipped with a shock absorber and/or spring, which arenot displayed in the figures. In this example there are no seat stays.

To reduce the width of the folded bicycle, folding pedals (11) can beused. Any form of pedals (11) can be used and mounted on the cranks(16). In one example, each crank (16) has a shorter stub (50) with abearing and a pedal (11), such as including a narrow pedal portion (52).Each pedal (11) preferably has associated with it a joint assembly (55),which enables folding of the outer footrest (60) portion of the pedal(11), and in the riding mode can provide a larger footrest foot seatingsurface.

The handlebar (34) is foldable. The middle part, which is attached tothe bearing assembly in the head tube (35), can be folded backwards anddownward, while each side (36) can be folded towards the frame (1), sothat the handles (37) are right next to the frame (1).

The middle shaft (22) also allows that the bicycle can be arranged as atwo-seat tandem without the extending of the frame. The second seatsupport (38) can easily be attached, and the shaft (22) can be equippedwith two additional cranks (39). The front and the rear pair of crankscan be aligned equally or with a 90-degree delay to allow both riders topedal undisturbedly. The direct transmission between the sprockets (23)and (24) enables synchronized rotation of the cranks. It is alsopossible to mount a pair of footrests (40) to the chain stays (17),instead of the additional cranks.

Since the wheels are of smaller size, preferably 16″ or alternatively23″ or other sizes, the spokes are less loaded, so the single-personframe could withstand the load of two persons as well.

The bicycle also can be equipped with brakes, lights, fenders, a standetc., as frequently provided in bicycles.

The design of the frame allows variations in shape and dimensions. Itcan be designed as a men's, women's, children's bicycle, or any othershape, without changing the essence of the invention, defined in thefollowing patent requirements.

Instead of chains, it is also possible to use drivebelts, preferablygeared drivebelts.

1. A folding bicycle comprising: a frame which has a top tube, a headtube, a down tube and a seat tube, a foldable front-wheel assembly whichhas a front wheel fork rotatably attached to the frame, and a frontwheel mounted to the front wheel fork, and a rear-wheel assembly whichhas chainstays (26) and a rear wheel mounted to the chainstays, whereinthe down tube is made of two tubes having a gap therebetween, andwherein the front-wheel assembly is foldable by rotating the front wheelfork by 180 degrees and folding it toward the down tube to therebypartially insert the front wheel into the said gap.
 2. The foldingbicycle according to claim 1, wherein the rear-wheel assembly isfoldable in that the chainstays together with the rear wheel can befolded around a pivot.
 3. The folding bicycle according to claim 1,further comprising a handlebar foldable towards the frame.
 4. Thefolding bicycle of claim 1, wherein the pivot has a shaft connected totwo coaxial sprockets, wherein front and rear chains are providedconnecting a chain ring provided on the frame and a rear sprocket,respectively, with the two coaxial sprockets.
 5. (canceled)
 6. Thefolding bicycle of claim 1, wherein the front wheel fork is equippedwith two swing-arms which hold the front wheel, and one end part ofwhich is pivotably coupled to the front wheel fork and the other endpart of which is coupled to a stirrup which in turn is connected to thefront wheel fork and which encloses a portion of the front wheel. 7-12.(canceled)
 13. The folding bicycle of claim 1 further comprising amotor.
 14. The folding bicycle of claim 1 further comprising a secondseat support attached to the frame and located behind a first seatattached to the frame.
 15. The folding bicycle of claim 1 furthercomprising cranks equipped with folding pedals.
 16. (canceled)
 17. Afolding bicycle comprising: a non-foldable, rigid frame composed of atop tube, head tube, down tube, and seat tube, a front-wheel assemblythat rotates and folds such that, when in a folded position, the frontwheel may be inserted in a gap between two down tubes, and a handlebarthat can rotate backward and downward toward the frame.
 18. A foldingbicycle comprising: a non-foldable, rigid frame composed of a top tube,head tube, down tube, and seat tube, and a front-wheel assembly thatrotates and folds such that, when in a folded position, the front wheelmay be inserted in a gap between two down tubes.
 19. A folding bicyclecomprising: a non-foldable, rigid frame composed of a top tube, headtube, down tube, and seat tube, and a front-wheel assembly that rotatesand folds.